Method for collecting IV tubing tips

ABSTRACT

Mandrel supported IV tubing is inserted within a mold of a mold assembly to heat the IV tubing and form a tapered end of the tubing. The tip of the tubing extending beyond the tapered end of the tubing is severed by the mandrel bearing against the mold to lodge the tip in an outlet of the mold. Cooling air is introduced to the mold assembly to cool the mold and to create a flow of turbulent air about the outlet of the mold to extract the severed tips. The turbulent air is exhausted through a channel, pipe and fitting into a collection chamber and causes translation of the severed tip to and into the collection chamber. Sensors may be incorporated to sense the translation of the severed tips.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is related to and claims priority to aprovisional application entitled “METHOD FOR RAPIDLY HEATING AND COOLINGA MOLD” filed Jul. 18, 2008, and assigned Ser. No. 61/081,969 and is acontinuation-in-part application of an application entitled “METHOD FORRAPIDLY HEATING AND COOLING A MOLD” filed Apr. 14, 2008 and assignedSer. No. 12/102,675, now U.S. Pat. No. 7,744,805, which is a divisionalof an application entitled “APPARATUS FOR RAPIDLY HEATING AND COOLING AMOLD”, filed Oct. 31, 2006 and assigned Ser. No. 11/555,172, now U.S.Pat. No. 7,438,548, which in turn is related to and claims priority froma provisional patent application entitled “ASSEMBLY FOR RAPIDLY HEATINGAND COOLING A CATHETER MOLD” filed Jan. 25, 2006 and assigned Ser. No.60/762,204 and a further provisional application entitled “RAPID HEATINGAND COOLING MOLD” filed Oct. 31, 2005 and assigned Ser. No. 60/732,118.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for rapidly heating andcooling a mold for foaming, molding or welding thermoplastic tubing and,more particularly, to a method for severing, and collecting the tips ofthe tubing after a tip cutting process.

2. Description of Related Prior Art

Molds used for forming, molding and welding plastic tubing have employeda resistive element associated with the mold and the tubing to be formedis disposed within the mold. Inductive heating of the mold has also beenemployed. Such heating has been at a fixed location on the mold withoutthe capability of varying the location of application of heat.

Molds used for forming, molding and welding tubing have been cooledprimarily through the use of massive heat sinks. The rate of cooling ofthe mold to permit withdrawal of the formed tubing is a function of theambient temperature and the massiveness of the heat sinks. Furthermore,some benefit has been achieved through dissipation of heat by radiationfrom finned heat sinks. Nevertheless, a significant time period isrequired to achieve the requisite cooling of the mold to permitwithdrawal of the formed tubing. Such time constraints negatively impactthroughput of the mold.

Prior art molds for use in conjunction with the forming, molding andwelding of tubing are in the nature of a composite or unitary assemblyhaving the requisite parts associated with one another to form a unit.If a different mold is to be used to achieve a different operation offorming, molding and/or welding of the tubing, a new unit must beconstructed. Without the capability of using substitutable subassembliesrelated to the mold itself, significant costs are incurred by having todevelop a complete unit for each type of operation to be achieved.

IV tip manufacturing processes have been in operation a long time.Despite the maturity of the IV tip manufacturing process, there does notexist a reliable and consistent apparatus or methodology for capturingexcess material resulting from the tip cutting process. In a typical IVtip manufacturing clean room, small particulates, byproducts of IV tipcuttings, cover the surroundings of an IV tipping station anddemonstrates the lack of existing methodology to capture this debris.

Detecting the presence of tip debris can provide a signal to either anoperator or a control circuit of the result of the tip cutting process.A lack of positive detection of the tip debris provides an alert toeither the operator or the control circuit of a system failure. Suchsystem failures may be indicative of production of bad parts. In anautomated environment, a failure of this type may be a significant setback. Presently, detection of a system failure is a function of the lackof tip debris and reliance is placed solely upon an operator tocontinually remain observant.

SUMMARY OF THE INVENTION

Apparatus for forming, molding or welding thermoplastic tubing, includesa dissassembleable housing that supports various components andaccommodates rapid and facile substitution of the components to satisfythe parameters of the various functions to be performed. A spoolsupporting a coil energized by radio frequency (RF) energy includes acentral aperture surrounded by the coil and is supported by the housing.A mold having a center section extends through the aperture in the spoolto locate the center section generally coincident with the coil. Amanifold provides a flow of air into the space between the centersection and the aperture to draw heat from the mold and to cool the moldafter the tubing has been formed, molded or welded. The mold isremovably mounted between the base and top of the housing to permitinterchangeability. A passageway extending through the mold permits useof a mandrel to support the tubing for a tipping operation. The mandrel,in combination with the mold, causes severance of the tip of the tubingupon formation of a taper of the tubing. The housing supports a manifoldthat injects streams of air into the space between the aperture in thespool and to the center section of the mold coincident with the severedtip. Upon severance of the tip, the air streams urge translation of thesevered tips through a passageway and into a collection chamber. Varioussensors may be used to confirm severance of the tip and count the numberof severed tips translated through the passageway.

It is therefore a primary object of the present invention to collectsevered tips resulting from carrying out an IV tip manufacturingprocess.

Another object of the present invention is to provide a flow of air tocause translation of severed tips of molded tubing to a collectionchamber.

Yet another object of the present invention is to provide a mandrelcooperating with a mold to sever the tip of a molded tubing.

Still another object of the present invention is to provide a collectionchamber for severed tips of tubing.

A further object of the present invention is to provide a coolingairflow about a low mass mold and to urge translation of severed tips ofIV tubing through a passageway and into a collection chamber.

A yet further object of the present invention is to provide a pluralityof sensors to confirm severance of a tip and count the number of tipssevered during a IV tubing tipping process.

A still further object of the present invention is to provide any ofseveral differently configured mold subassemblies that may beinterchangeably replaced within a housing to form, mold, or weld IVtubing and collect each tip severed from the tubing.

These and other objects of the present invention will become apparent tothose skilled in the art as the description thereof proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described with greater specificity andclarity with reference to the following drawings, in which:

FIG. 1 is a schematic diagram illustrating major components of thepresent invention and their interconnections;

FIG. 2 illustrates the platform and the equipment mounted thereon;

FIG. 3 is a cross sectional view of the platform and equipmentillustrated in FIG. 2;

FIGS. 4A, 4B, 4C and 4D illustrate various views of the mold assembly;

FIG. 5 illustrates an exploded view of the mold assembly;

FIG. 6 illustrates a cannula tip and a mandrel for insertion therein;

FIG. 7 illustrates the mandrel inserted within the cannula tip;

FIG. 7A is a partial view taken within the dashed lines shown in FIG. 7;

FIG. 8 illustrates the support and feed unit for receiving the cannulatip and mandrel;

FIG. 9 illustrates the translation of the support and feed unit towardthe mold assembly;

FIG. 9A is a cross sectional view illustrating the IV tubing and mandrelinserted within a mold;

FIG. 10 is a detailed view illustrating the interaction of the mandrelwith the mold;

FIG. 11 illustrates the severed tip of the IV tubing;

FIG. 12 illustrates the turbulent air attended the severed tip of the IVtubing;

FIG. 13 illustrates the translation of the severed tip through apassageway to a collection chamber;

FIG. 14 illustrates a potential plurality of severed tips;

FIG. 15 illustrates the translation of a plurality of tips through apassageway in response to an imposed air flow;

FIG. 16 illustrates translation of a severed tip through a passageway;

FIG. 17 illustrates further translation of the severed tip; and

FIG. 18 illustrates the severed tip arriving within a collectionchamber.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the formation of IV tubing, sometimes referred to as a cannula tip ora stylet tip, the end of the tubing is tapered and the tip is cut off.The cut off tip amounts to debris to be discarded. In a production run,it is important to identify the presence of each cut off tip to ensurethat the IV tubing is properly formed and that the manufacturing processis functioning normally. The apparatus for forming the IV tubingincludes a source of air flow for cooling the attendant low mass mold.The air flow is also channeled through passageways to urge translationof the cut off tips past sensors for detecting the presence of cut offtips and into a collection chamber.

FIG. 1 illustrates a mold apparatus 10 for forming IV tubing. Inparticular, a platform or housing 12 supports mold assembly 14. Theinsertion and withdrawal of a mandrel, along with insertion andwithdrawal of plastic tubing, into and from a mold assembly is providedby a support and feed unit 16. It is to be understood that this unitalso supports the mandrel prior to and after insertion into the moldassembly. The air for mold cooling purposes is provided by air supply 18conveying air under pressure through a conduit 20 to the mold assembly.An RF generator and control circuit is connected to support and feedunit 16 through conductor(s) 24. The signals transmitted by the controlcircuit through conductor(s) 24 may control the transport of the mandrelsupported tubing into the mold, the duration the tubing is within themold and the withdrawal of the tubing. Through a further conductor(s)26, RF energy is supplied to a coil in a spool to cause the coil toinductively heat an encircled center section of a mold. A furtherconductor(s) 28 provides feedback signals to RF generator and controlcircuit 22. These feedback signals may be of many types, includingtemperature indication at one or more signals reflective of the air flowrate and/or temperature.

Referring jointly to FIGS. 2 and 3, there is illustrated an embodimentof mold apparatus 10. Housing 12 supports mold assembly 14, support andfeed unit 16 and a collection chamber 30. The above described source ofair supply 18 is connected to conduit 32 in fluid communication with themold assembly. An air flow channel 34 extends from within mold assembly14 into fluid communication with a pipe 36. This pipe is coupled with ahollow fitting 38 extending into collection chamber 30. The collectionchamber includes a plurality of vents 40 that may be disposed in top 42of the collection chamber. Unit 16 is slideably mounted on housing 12 toaccommodate translation of mandrel supported IV tubing 44 into and outof mold assembly 14.

Referring jointly to FIGS. 4A, 4B, 4C and 4D there is shown moldassembly 14 having enclosure 50 formed by a bottom 52 and a top 54. Amanifold 56 is disposed on the left side and is in fluid communicationwith a conduit 32 functionally connected to a source of air underpressure (not shown). A flange 58 of a mold 60 may extend from the rightside of enclosure 50, as illustrated. A pair of conductors 62 may extendfrom within the enclosure for connection to an RF generator.

Referring particularly to FIGS. 4B, 4C, and 4D, certain structureinternal to enclosure 50 will be described. Top 54 and bottom 52 ofenclosure 50 are secured to one another by bolts 64, 66 extendingthrough apertures in top 54 and into threaded engagement with bottom 52.Mold 60 extends into enclosure 50 and may be threadedly engaged withcone 68 disposed within manifold 56. A spool 70 includes a centralaperture for penetrable engagement with mold 60. Conductors 62 arewrapped about the spool to form a coil and, upon energization, willcause inductive heating of the circumscribed central section of themold.

FIG. 5 illustrates an exploded view of the basic components supported byenclosure 50. Manifold 56 includes a cylinder 72 having a cone shapedinterior surface commensurate with the surface of cone 68 but of largersize to provide a cone shaped space therebetween. Cylinder 72 includesan inlet 74 in fluid communication with conduit 32 to introduce air intothe space between the cylinder and the cone. Cylinder 72 includes anannular ridge 76 for engagement with a correspondingly sized partialannular groove 78 formed in bottom 52 and a partial annular groove 80formed in top 54. Spool 82 includes a threaded passageway 84 in at leastone of the discs forming the spool and a further passageway 86 in eachof the discs forming the spool. A machine screw 88 is supportedintermediate bottom 52 and top 54 in commensurately configured groovesand it is in threaded engagement with threaded passageway 84. A pin 90is rotatably supported in commensurate grooves in bottom 52 and top 54and is in non threaded penetrable engagement with passageways 86. Uponrotation of screw 88, spool 70 will be translated left to right andright to left and rotation of the spool is precluded by its slidingengagement with pin 90. Mold 60 extends through and in non contactingrelationship with aperture 92 formed at the center of spool 70 to forman annular space between the aperture and the encircled mold. In oneembodiment, end 94 of the mold may be in threaded engagement with thecenter of cone 68.

Referring to FIG. 6, there is shown IV tubing 100 formed by a body 102supporting a length of plastic tubing 104 extending therefrom and priorto formation of a taper at the tip of the length of plastic tubing 104extending therefrom and prior to formation of a taper at the tip of thetubing. A mandrel 106 includes an end 108 having an annular sharp edge.A collet 110 is mounted on the mandrel at a location commensurate with apredetermined penetration of the mandrel through tubing 104. Referringjointly to cross sectional views in FIGS. 7 and 7A, mandrel 106 is showninserted through body 102 and into tubing 104. The degree of insertionof the mandrel within the tubing is a function of the degree ofextension 112 of the tubing past end 108 of the mandrel. For differentdiametric sizes and wall thicknesses of the tubing, the length ofextension 112 may vary. It may be noted that the degree of extension ofthe mandrel within the tubing is a function of the location of collet110 upon the mandrel; this location is adjustable as a function of thecharacteristics of the tubing and the nature of the tipping to beperformed on the IV tubing.

Referring to FIG. 8, there is illustrated support and feed unit 16 priorto placing assembly 114, consisting of IV tubing 100, mandrel 106 andcollet 110, thereon. The support and feed unit includes a V-shapedsupport 116 for supporting mandrel 106 at the apex of the support. Theinterior side 118 of unit 16 bears against the rear surface of collet110. A further V-shaped support 120 supports a combination of tubing 104and internally located mandrel 106. By using V-shaped supports of thistype, the mounting of assembly 114 is an easily accomplished task. Byusing the V-shaped supports, self-alignment of assembly 114 with supportand feed unit 16 is automatic. Furthermore, after the tip of the tubinghas been formed, removal of assembly 114 amounts to nothing more thanlifting the assembly from the feed and support unit.

After mounting assembly 114 on support and feed unit 16, the unit istranslated toward mold assembly 14 as depicted by arrows 122, 123 and124 in FIG. 9. Supports 116, 120 of the support and feed unit accuratelyalign tubing 104 and supporting mandrel 106 with inlet 128 of mold 130.This mold is equivalent to mold 60 illustrated in FIGS. 4A, 4C, 4B and5. On completion of translation of the support and feed unit, asdepicted in the cross sectional view shown in FIG. 9A, mandrel supportedtubing 104 is lodged within mold 130.

Upon insertion of mandrel 106 supported tubing 104 (assembly 114), mold130 is heated. As particularly depicted in FIGS. 10 and 11, the moldincludes a cylindrical section 132 terminating in a shallow cone shapedsection 134. The end of section 134 includes a truncated cone shapedsection 136 having a more angular orientation relative to cone shapedsection 134 and an internal diameter less than the diameter of mandrel106. Upon extension of mandrel 106 into mold 130, end 108 (see FIG. 7A)will bear against and come into contact with truncated cone shapedsection 136. Because of the sharp circumferential edge of end 108, itwill cause a cutting of extension 112 of tubing 104 extending beyond theend of the mandrel, as shown in FIG. 7A. This cutting function producesa severed tip 140 lying within circular passageway 142 of mold 130.

As depicted in FIG. 3 and FIG. 12, conduit 32 is in fluid communicationwith a source of air flow for cooling mold assembly 14. This air flow ischanneled through passageways 144, 146, as depicted by arrows 148, 150.The air flow continues from each of these passageways to a commonchamber 152, as depicted by arrows 154 and 156. This chamber surroundssection 158 of mold 130 wherein tubing 104 is actually formed into atapered configuration. As depicted by circular arrows 160, 162 proximateopening 142 of passageway 144, turbulent air flow will exist adjacent tothe opening and into passageway 144. This turbulent air flow isexhausted through channel 34 (see also FIG. 3), as depicted by arrow164. The turbulent air flow (arrows 160, 162 depicted in FIGS. 12, 13,14 and 15) will have the effect of extracting severed tip 166 fromwithin passageway 144. Furthermore, the air flow (depicted by arrows 164through channel 34) will urge translation of severed tip 166 along thechannel as illustrated in FIG. 13.

Under certain circumstance a severed tip 166 may remain lodged withinpassageway 144 instead of being extracted by the adjacent turbulent airflow. Such situation is depicted in FIG. 14 wherein two severed tips arelodged within the passageway. Subsequent molding operations will producean additional severed tip with each operation. The accumulation of thesesevered tips will result in the front most tip ultimately becomingdirectly subjected to the turbulent air flow attendant opening 142 ofpassageway 144. Because the severed tips are relatively light weight andthe turbulent air flow exerts a force thereon, extraction of a foremosttip will ultimately occur. With the extraction of the foremost severedtip, a greater or lesser extraction force due to turbulent air flow within passageway 144 will urge extraction of any remaining severed tips.Upon such extraction, one or more severed tips will be conveyed intochannel 34 as depicted in FIG. 15.

As depicted in FIGS. 16, 17 and 18, severed tip 166 will be translatedthrough channel 34 into pipe 36. Thereafter it will flow into fitting 38and be exhausted therefrom into collection chamber 30. As depicted inthe drawings, the diameter of channel 34 is less than the diameter ofpipe 36. Such increase in diameter will result in proportional decreaseof flow rate of the air flowing therethrough. Fitting 38 includes acylindrical passageway 168 of a diameter significantly greater than thatof pipe 36. The commensurate reduction in air flow rate will slow thetranslation of severed tip 166 therethrough. With the reducedtranslation speed of the severed tip, it is likely that it will drop tothe bottom of collection chamber 30. Moreover, the reduced air flow rateexhausting from passageway 168 will have a minimal effect upon anymovement of severed tips already lodged in the collection chamber. Asnoted with respect to FIG. 3, the collection chamber includes vents 40in the top surface for exhausting the air flow. The combined area of thethese exhaust vents is significantly greater than the cross sectionalarea of passage 168 which causes the rate of flow of exhaust air to besignificantly reduced. Such reduction in flow rate minimizes thelikelihood of any severed tips becoming lodged in the exhaust vents.

As represented by module 170 disposed intermediate channel 34 and pipe36, shown in FIG. 17, sensors of any of various types may be lodgedtherein or elsewhere along the length of channel 34, pipe 36 orpassageway 168 to sense translation of a severed tip there passed. In ahigh production or mass production version of the present invention itmay become critical to ensure the passage of each severed tipcommensurate with the formation of the IV tubing. Without suchconfirmation, there may be an indication of faulty operation, breakage,or other production halting situation. To minimize downtime and toensure accuracy and completeness of the IV tubing formation process,such sensing may be critical.

1. A method for collecting severed tips of IV tubing after formation ofa taper to the end of the IV tubing, said method comprising the stepsof: a) inserting a mandrel into the IV tubing short of the end of the IVtubing to define an extension of the IV tubing; b) forming the mandrelsupported IV tubing into a taper within a mold cavity of a moldassembly; c) severing the tip of the IV tubing represented by theextension of the IV tubing by urging the end of the mandrel intointerfering engagement with the mold cavity; d) providing a source ofair flow adjacent the mold cavity to urge translation of the severed tipout of the mold cavity; e) urging translation of the severed tip fromthe mold cavity through a passageway downstream from the mold cavity andinto a collection chamber.
 2. The method as set forth in claim 1including the step of mounting the mandrel supported IV tubing in asupport and feed unit.
 3. The method as set forth in claim 1 whereinsaid step of severing includes the step of urging the end of the mandrelagainst a truncated cone section in the mold cavity to sever the tip. 4.The method as set forth in claim 3 including the step of lodging the tipin the passageway downstream from the mold cavity, which passagewayincludes an opening at the ingress of the passageway.
 5. The method asset forth in claim 4 wherein said step of providing creates a turbulentair flow adjacent the opening to urge extraction of the tip through theopening.
 6. The method as set forth in claim 1 including the step ofsensing the passage of a tip through the passageway.
 7. The method asset forth in claim 1 including the step of reducing the flow rate of theair flow toward the collection chamber.
 8. The method as set forth inclaim 7 including the step of exhausting air from the collection chamberat a flow rate less than the flow rate through the passageway.
 9. Themethod as set forth in claim 2 including the step of removing the formedIV tubing from the support and feed unit.